1. Technical Field
The present disclosure is directed to color measurement systems and methods and, more particularly, to systems and methods for multi-standard color-measurement, whereby color-measurements based on a first color measurement standard may be selectively restandardized.
2. Background Art
Color-measuring instruments, such as spectrophotometers and calorimeters, are generally employed in making color measurements in a variety of laboratory and production environments. For example, color measurements are used in determining whether the color of an article being produced meets the applicable color specifications. Color-measuring instruments generally produce color measurement data that is based upon a color coordinate system, e.g., CIELAB. However, even when the same color coordinate system is utilized by color-measuring instruments manufactured by different instrument manufacturers, the color measurements generated by such instruments frequently differ for a variety of reasons.
For example, color-measuring instruments manufactured by different instrument manufacturers may generate different results because the instruments: (i) are calibrated to different standards (e.g., the white standard of NPL vs. the white standard of NIST); (ii) utilize different correction modalities to address linearity of data measurement results; (iii) have physical and/or structural differences that affect color measurements; and/or (iv) employ differing approaches to illumination, e.g., as to bandwidth, wavelength, etc. For purposes of the present disclosure, differences in color measurement data that result from one or more of the structural/functional differences described above (or from other such structural/functional differences) are referred to as resulting from differences in “color calibration standards.”
Thus, color measurement data generated by a first color-measuring instrument may not be directly comparable to color measurement data from a second color-measuring instrument based on differing color calibration standards. Indeed, the color measurement data generated by the first color-measuring instrument may be characterized by a first centroid, whereas the color measurement data generated by a second color-measuring instrument may be characterized by a second centroid, wherein the first and second centroids are characteristics of the respective color-measuring instruments.
The ability to compare color measurement data is often of significant importance in commercial applications of color-measuring instruments. Color performance is often used as a litmus test for manufacturing quality. The importance of color measurement data assessment is heightened by challenges associated with multi-site enterprises, extended supply chains, compressed cycle times, and limits on resources and expertise in the field of color measurement and management. For example, it may be desirable to produce parts of the same color at multiple locations with the business requirement that the parts match in color when assembled. Color matching is also important in production of replacement parts. Because color-measuring instruments produced by different manufacturers are frequently subject to different color calibration standards, fundamental difficulties arise in comparing color measurement data generated by spectrophotometers/colorimeters from different manufacturers.
Thus, a user at one location measuring a color sample using a color-measuring instrument from a particular manufacturer is likely to obtain color measurement data that is different from the color measurement data obtained by a user measuring the same color sample at a different location using a color-measuring instrument produced by another manufacturer. Similarly, matching colors may become difficult where the standard color specifications are generated based on color calibration standards employed by a color-measuring instrument produced by a first manufacturer, while another manufacturer's instrument is to be used to test the article being produced.
Accordingly, systems and methods are desired whereby color measurement data generated by different color-measuring instruments could be selectively standardized to a desired color calibration standard. In addition, systems/methods for automatically transforming spectral data as part of a communication regimen between color-measuring instruments is needed to enhance operations that involve or rely upon color measurements, e.g., operations that are situated at multiple locations and/or that are using color-measuring instruments from different manufacturers.